This invention relates to data processing systems and printer subsystems but more particularly concerns the determination of the extent and direction of movement of movable devices therein, such as forms feed assemblies.
During operation of such systems or subsystems it is necessary that the Controller, such as a microcontroller, be able to keep accurate control of the movement of associated devices. As described, a microcontroller of this nature issues commands to the particular device to start movement in at least one direction and thereafter monitors by means of detection of signals from an emitter or similar timing device, not only the fact that movement has started but the extent of movement and its direction. It has been difficult for the microcontroller to accurately determine these factors and expensive hardware is necessary to perform this task.